The cursor changes to: . Press the left mouse button on one part of the graph, where the limits should begin/end.

Hold down the cursorand drag the mouse to the other side of the graph, where the limits should begin/end. Notice the rectangle and triangle drawn on the screen as you drag the bounding box (highlighted in the image in red). The triangle should always remain inside the limits of the existing ternary diagram. The triangle is approximately the size of the new limits.

Highlight the desired axis limits by dragging a box around that part of the graph.

Release the cursor and the axis limits for all three axes update.

You can also adjust the ternary axis limits using numbers in the advanced dialog. This can be used to adjust the previous limits or this can be done from the beginning if you know the exact limits you want. To do this,

Click on any of the axes in the Object Manager to select it.

In the Property Manager, click on the Axis tab.

In the Limits section, click the Enter limits button next to the Advanced command.